. Model making; including workshop practice, design and construction of models, a practical treatise for the amateur and professional . Fig. 45—Showing the use of a * * V-Block spindle down until the drill touches the center dot. Per-mit the drill to go just far enough to drill the dot off,then raise the spindle, and, by means of the small circlescratched on the plate, see if the tiny indentation made 70 Model Engineering is exactly in the center, nsing the circle as a guide. If itis properly centered, drill jnst a little further (do notpermit the point of the drill to go very far b
. Model making; including workshop practice, design and construction of models, a practical treatise for the amateur and professional . Fig. 45—Showing the use of a * * V-Block spindle down until the drill touches the center dot. Per-mit the drill to go just far enough to drill the dot off,then raise the spindle, and, by means of the small circlescratched on the plate, see if the tiny indentation made 70 Model Engineering is exactly in the center, nsing the circle as a guide. If itis properly centered, drill jnst a little further (do notpermit the point of the drill to go very far below thesurface) and follow out the same operation on each cor-ner. When the %-inch hole in the center is drilled, gocautiously until the drill is centered accurately, and do. Fig. 46—Plate showing the holes started after the circles are made not bore right through the plate without raising the spin-dle several times to see that the drill is in the exact cen-ter. Fig. 46 will make this clear. Those amateur mechanics who have tried to drill atransverse hole in a piece of roun^ stock know what adifficult matter it is to do it accurately. This can easilybe accomplished, however, by the use of a V-block, and,as these can be purchased for a few cents, the mechanicis urged to procure one. Their use is shoAvn in the pho-tograph. Fig. 45. In^the event the mechanic desires tomake one for himself, it can easily be done on a shaper,and the sides of the groove are cut at exactly 45 degrees. The rate of feed and speed for small bench drillsshould vary with the diameter of the drill and the hard-ness of the metal being drilled. As a general rule, smalldrills should be run at high speed and larger ones atlower speed. An easy method of obtaining the approxi- Drills and D
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Keywords: ., bookcentury1900, bookdecade1910, bookidmodelmakingi, bookyear1919
